81848857 has 4 divisors (see below), whose sum is σ = 81867700. Its totient is φ = 81830016.

The previous prime is 81848843. The next prime is 81848867. The reversal of 81848857 is 75884818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 30239001 + 51609856 = 5499^2 + 7184^2 .

It is a cyclic number.

It is not a de Polignac number, because 81848857 - 2¹⁵ = 81816089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81848857.

It is not an unprimeable number, because it can be changed into a prime (81848807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 769 + ... + 12817.

It is an arithmetic number, because the mean of its divisors is an integer number (20466925).

Almost surely, 2^81848857 is an apocalyptic number.

It is an amenable number.

81848857 is a deficient number, since it is larger than the sum of its proper divisors (18843).

81848857 is a wasteful number, since it uses less digits than its factorization.

81848857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18842.

The product of its digits is 573440, while the sum is 49.

The square root of 81848857 is about 9047.0358129058. The cubic root of 81848857 is about 434.1810584066.

The spelling of 81848857 in words is "eighty-one million, eight hundred forty-eight thousand, eight hundred fifty-seven".